The present invention tackles the problem of receiving signals in a discontinuous flow and with a high bit rate. This problem arises, for example, within the switching nodes of packet-switched optical networks.
A signal corresponding to a flow of data of the type described above is shown schematically in FIG. 1. Essentially, this is a flow of data at a high bit rate (fc), transmitted from a remote system along an optical fibre, for example, and intended to be received in a receiving device. The data flow in question is structured in packets with a duration of Tp, separated by xe2x80x9cguard timesxe2x80x9d, denoted by Tg, in which no data are transmitted. The time interval between the initial instants of two packets Pi, Pi+1, etc., received in succession is therefore denoted by the interval Ts, where Ts=Tp+Tg. If fc and Tp are known, then the number N of bits in the packet is also known: N=fcxc3x97Tp.
The problem of the reception of discontinuous data flows of the type specified above arises essentially from the fact that, even if the phase of the data in each packet does not vary significantly throughout the duration of the packet, the packets received in succession usually have phases which are completely uncorrelated with each other.
The object of the present invention is to provide a device capable of enabling data flows of the type described above to be received in a precise and reliable way.
According to the present invention, this object is achieved by means of a receiver having the characteristics called for in the following claims. The invention also relates to the corresponding process of reception.
Briefly, the solution according to the invention provides for the execution, at the time of reception of each packet, of a kind of xe2x80x9cpre-readingxe2x80x9d of at least part of the packet, with the purpose of acquiring the information relating to the phase (and, preferably, also the mean signal power) of each packet. The information thus acquired is then used for the execution of the actual reading operation.